GUIDE: PROF S. R. KULKARNI
GAJANAN R. HANGE
Lubricating oil are viscous liquids used for lubricating
moving parts of engines and machines. Eg. Engine oils, gear
oils, hydraulic oils, turbine oils, grease etc.
Used to reduce friction between moving surfaces.
Remove heat from working parts in Machinery.
Remove wear debris created by moving surfaces.
Provide a protective layering on metal surfaces to avoid
Removing contaminants from the engine.
USED LUBE OIL
Used lube oil is defined as the petroleum derived or
synthetic oil which remains after applications in
lubrications, cutting purposes, etc.
Build up of temperature degrade the lubricating oil, thus
leading to reduction in properties such as : Viscosity,
Specific gravity, etc
Dirt and metal parts from the surfaces are also
deposited into the lubricating oils.
With increased time of uses, the lubricating loses its
lubricating properties as a result of over reduction of
desired properties and thus must be replaced with fresh
CONTAMINANTS IN USED LUBE OIL
The main contaminants are :
WATER :Fuel burns to CO2 and H2O. When an engine is cold the water
Created can pass through to the lube oil.
FUEL : Unburned petrol or diesel passes through to the lube oil during
CARBON : Forms as a result of incomplete combustion when an
engine is warming up and passes through to the lube oil.
DUST : Small particles pass into the engine through the air breather.
METALS : Due to normal engine component wear.
OXIDATION PRODUCTS : Additive chemicals at elevated temperatures
in the presence of oxygen can oxidize forming corrosive acids.
FACTS ABOUT HAZARDUS NATURE
OF USED OIL
Used oil themselves are not toxic. Contaminants such as additives,
degradation products, make them so hazardous.
They have high potential to cause damage to the environment by
virtue of their persistent nature and potential to spread over large
surface areas on land and water.
Films of oil prevents light and air from reaching to life forms on
land and water.
As per the data one liter of oil can spoil one million liters of pure
ENVIRONMENTAL ISSUES CAUSED BY USED
Oil, in any form, is potentially harmful to the environment.
In aquatic community oil residue tends to settle on the
bottom, coating the substance and whatever organisms live there.
When poured on the ground, oil can rapidly migrate through the soil.
In both instances bacteria, plants, invertebrates and vertebrates
experience physiological stress.
Oil film on water can reduce the penetration of light into the water
and, consequently, reduce the rate of photosynthesis. When
photosynthesis is reduced, oxygen production is also reduced.
NEED FOR RE REFINING
The need to conserve crude reserves.
Minimizing unemployment through the building of used lube
oil recycling plant.
The elimination of environment pollution.
IMPORTANCE AND BENEFITS OF
Reduce dependence on base oil imports saving foreign exchange.
Prevent ground water contamination and pollution.
Preserve natural resources such as coal and crude oil.
Reduce sewage treatment costs.
Eliminate improper burning of waste oil as fuel, which generate
toxic fumes and air pollution.
PROCESS INVOLVED IN USED OIL RE-REFINING
Step 1 - Dehydration
The oil is boiled in a closed container to remove the water that has
been mixed into it.
Step 2 - Diesel stripping
The dehydrated oil is then fed continuously into a vacuum distillation
fractionation. Lighter oils boil off first and are removed, followed by
the lubricating oil itself. Other heavier components do not boil in the
Step 3 - Lube oil distillation and condensation
A liquid extraction process then removes any aromatic components
from the oil. By this stage, the oil is identical to refined virgin oil.
VACUUM DISTILLATION PROCESS
dehydrated oil is fed continuously into a vacuum
distillation plant for fractionation. The fractions obtained
are as follows:
1.Light fuel and diesel : Oil produces enough diesel from
the used oil feedstock to run all the burners and
boilers, giving total self-sufficiency in fuel.
oil : The bulk of the feedstock will distill
off in the plant to produce a lubricating oil fraction.
: The non-distillable part of the feedstock.
This contains all the carbon, wear metals, degraded
additives and most of the lead and oxidation products.
LUBE OIL DISTILLATION AND
Then a liquid extraction process is done in the presence of
solvent N-methylpyrolidone (NMP).
The NMP is an aromatic selective solvent which removes
some color and odour.
Also it is able to extract all unwanted aromatic
contaminants present in lubricating oil fraction.
Used oil is pollutant, and, by re-refining, the pollution is
reduced. Hence, it should get the status of eco-friendly
technology and get grants and incentives from the
Minister of the Environment.
Since re-refining leads to oil conservation, the concept
of re-refining should be strongly supported by the
Petroleum Conservation Research Association.